Protester douses himself in petrol

"HI guys - if I don't make it out of this alive thanks for all your support over the years - please help out *** and the kids with the future."

That's the intimidating post a man put on Facebook as he engaged in a tense standoff with police in Canberra.

After more than two hours, discussions with police negotiators caused Harry Longworth to end his protest and hand himself over on his own volition shortly after 2.40pm AEDT.

Police immediately moved to search and secure his vehicle.

A photo posted by a man who has allegedly doused himself with petrol, showing police negotiators approaching. Picture: Facebook

Longworth began his protest by parking his four-wheel drive on a median strip on Anzac parade between two office buildings. A large number of police and a fire truck responded.

"It's the petrol that the nice people are most worried about," the man had posted on Facebook during the early stages of the standoff, adding that police negotiators had put on bulletproof vests before attempting to speak with him.